This invention pertains to a method and apparatus for non-invasive determination of disorders of human joints, in general, and a method for determining the dynamic biomechanical parameters of the cervical spine, in particular.
Analysis of neck injury caused by hyperextension of the head, often followed by strong flexion due to excessive acceleration and deceleration of the body has been lacking and the corresponding ability to diagnose the likelihood of injury as well as the specific location of injury has been limited. Injuries and disorders of the cervical spine often are soft tissue injuries and as such are not readily ascertainable by means of conventional diagnostic aids such as x-ray, MRI, CT-scan, or other tissue penetrating imaging devices. Consequently, the confirmation of neck injury tends to be a subjective diagnosis.
Even where it is indisputable that a patient has suffered an injury to the cervical spine, there is no objective determination available which will enable medical personnel to determine progress in recovery from the injury or effectiveness of different types of treatment of the injury. In addition, it would be desirable to have a clinical method for determining the status of an individuals cervical spine before, during and after engagement in specific activities. Yet even further, it may be desirable in certain circumstances to be able to determine the incidence of neck injury in certain populations of individuals.
Significant effort has been directed to the formulation of reliable techniques and apparatus for measuring movement of human body parts. In particular, U.S. Pat. No. 5,203,346 to Arlan W. Fuhr et al describes a method and apparatus for the non-invasive determination of kinematic movement of the cervical spine. The Fuhr arrangement provides a non-invasive method and apparatus for determining a patient's three dimensional helical axis of rotation during specific movements. It is suggested in the Fuhr patent that the head axis of rotation is then used with normal data bases for diagnosis of abnormal kinematic function of the cervical spine.
In the illustrative embodiment described in the Fuhr patent, video cameras are utilized to record movement of markers carried on the patient's head as the patient moves his/her head through specific head movements. A head mounted light source acts as a pointer so that the patient receives instantaneous feedback as to the position of his head. A planar array of vertical, horizontal and oblique oriented lines is placed on a wall. The array includes circular landmarks to depict specific angles. The patient is instructed to perform a series of voluntary range-of-motion tasks to provide the outside parameters of his/her range-of-motion for the actual test. The patient starts by making standard, voluntary, self-paced, slow range-of-motion movement in the flexion-extension (down-up), axial rotation (left-right), and lateral bending (side-to-side) directions. Following the voluntary range-of-motion tasks, the patient is instructed to follow target patterns within his/her voluntary range-of-motion. Four target patterns are used: left-right, up-down, a box pattern in either direction, and an oblique or x-shaped pattern.
While the patient is following the target pattern, movement of the markers are recorded on videotapes for further processing. Data recorded on the videotapes is processed to calculate various screw axis parameters and to plot same. The derived plots are then compared to standard plots and/or to prior plots of the same patient so that the nature and/or extent of the abnormal kinematic movement of the cervical spine can be determined.
Although the method and apparatus shown and described in the Fuhr patent has provided a significant advance in the ability to measure kinematic function of the cervical spine, the method and apparatus requires analysis of video taped motions of a each patient which takes a relatively long period of time to provide quantitative data. In addition, the apparatus and method of the Fuhr patent is principally for the determination of certain parameters.
It therefore is one object of the invention to provide a method with which the kinematic function of a human joint may be determined.
It is yet a further object of the invention to provide a method of determining normal or acceptable biomechanical parameters for joint kinematic movement.
It is a further object of the invention to provide a method and apparatus which may on a non-invasive basis determine the health status of a patient's joint.
These and other objects of the invention are provided by a method and apparatus in accordance with the invention as described herein.